Crossing the Line
by ch1ps0h0y
Summary: When does hate become love? The boundary between the two is always unclear.  A Mukuro x Hibari fic


There it was again - that gentle probe which indicated an intrusion on his mind. Hibari twisted in his seat to narrow his eyes at the man standing in the doorway of the small library in the Vongola's underground headquarters, and firmly pushed away the presence in his head.

"Don't intrude upon others like that. Say what you want then leave, Mukuro," Hibari told the man.

With a languid shrug, the Guardian of Mist replied, "I was bored."

Hibari turned back to his computer. "Then go and find some entertainment." The sharp tapping of keys resumed beneath his fingers.

"That was why I came to you." Hibari sensed Mukuro approach from behind on soft footsteps and lean over his shoulder. "Are you working again?"

"Yes." More tapping.

"A pity. I wanted to have a quick spar," Mukuro sighed.

"Find someone else." Hibari focused pointedly on the computer screen, hinting at the other man to go away and leave him in peace.

"No-one else is a strong enough adversary." Then speaking with his mind: _Please? Or I'll force you to_.

Hibari's reaction was instantaneous, standing and kicking his chair backwards then tackling the taller man to the ground while Mukuro was still off-balance. They and the chair crashed to the floor with Hibari leaning on top of Mukuro.

"Don't do that ever again," the shorter man said harshly. He frowned when Mukuro laughed. "What?"

Mukuro's eyes glittered with amusement. "I made you get up and fight me."

"Hmph." Hibari stood and picked his chair up from where it had fallen, placing it back behind his desk. Without warning he felt his feet swept out from under him – but not by anything physical. He landed painfully on his back and white spots flashed before his vision as his head impacted on the metal floor. Despite his pounding head, Hibari managed to glare as Mukuro – now sitting upright – leaned over him. The other man tilted his head and gazed back innocently but could not stop a smile twitching at the corners of his mouth. Hibari tried to push himself back up but found his limbs would not respond.

"Let me go," Hibari said evenly. Inwardly, he seethed at the fact that the other man still maintained such control over him.

"No. If you don't want me in here," Mukuro tapped a finger on Hibari's forehead, "then you will have to fight against me."

Hibari's mouth set itself in a fierce slant. He pitted his raw anger against Mukuro's mind control, slowly forcing the man out of his head, ignoring the dizzying headaches and spikes of pain that stabbed through his skull. The moment full bodily control returned to him, Hibari swung his fist upwards.

Mukuro easily blocked the fist and the other which followed. He chuckled. "Much faster than the last time," he commented, smiling infuriatingly.

"If you're satisfied then leave me to my work." Hibari wrested his arms from Mukuro's grasp and sat up, still glaring at the Mist Guardian.

Mukuro glanced at the computer. "Always, always busy," he murmured. Impulsively, he reached out and ran a hand along the Hibari's cheek then snatched it back, but not fast enough to avoid Hibari grabbing his arm.

"You don't like it when I'm busy? Then you have too much free time. Aren't _you_ always on missions?" Hibari's eyes did not waver from Mukuro's as he spoke.

"But every day you sit here, typing away. You have to keep practising or you will not remain the strongest fighter of the Vongola." A sly look crept across Mukuro's face. "And then how you will keep defeating me?"

Hibari tightened his grip on the arm he held. "You're trying to provoke me. I won't fall for all your tricks, Mukuro. I know you better now." The other man merely gave him a lazy smile. Something in Hibari's chest thudded painfully at it but he forced his rational self to see through what was clearly meant to charm.

"I quite like your face when it's not set in a perpetual frown, Kyoya," Mukuro teased, noticing the slip-up in the other's expression. "Was it something I did?" He was jerked forward by the loose tie he wore and a voice growled into his ear:

"Bastard, you know it was." Mukuro started to grin then flinched when a set of teeth scored a painful bite on his neck. "That was for distracting me from my work. I'll deal with you properly later."

"I'm looking forward to it," Mukuro murmured, running fingers through the other Guardian's jet-black hair much to the latter's annoyance.

It was at this moment that Tsuna walked into the room.

* * *

It was not quite the situation Tsuna had wanted to interrupt Hibari in. In fact, it was possibly one of the worst so far. He did _not_ want to be present during one of Hibari and Mukuro's rows. He tried to back away before he was noticed but Hibari's unusually sharp senses had already detected his presence.

"Tsunayoshi. What are you doing?"

Sighing, the Decimo abandoned his retreat. He tried not to cringe under Hibari's flat gaze and avoided Mukuro's questioning glance.

"What do you want?" Hibari asked. As direct to the point as ever.

"I just wanted to check up on the progress of your research..." Tsuna trailed off, trying not to stare at the pair for too long. He cleared his throat timidly. "Am I interrupting...?"

"No." Hibari let go of Mukuro, letting the other fall back. He stood and folded his arms, regarding his superior with that calm and neutral expression Tsuna knew hid a multitude of thoughts. "This bastard was just leaving."

"I can come back later..."

"Stay, Tsunayoshi. I will go." Mukuro was now on his feet and readjusting his jacket. Without another word, he strode briskly from the room. Tsuna was not quite able to suppress a shiver as the man passed him.

"Are you going to waste my time further?" Hibari's impatient voice cut through Tsuna's lapse in attention, making him jump.

"I-I need either you or some of your men to scout this location for me..."

* * *

"_I will bite you to death_!"

Mukuro danced backwards as the speaker launched themselves at him. All manner of food and cutlery went flying, along with the table which it had all rested upon just seconds ago. The rest of the Family (minus Tsuna, who was absent at the moment) backed away quickly, distancing their selves from the quarrel. Mukuro laughed as he dodged around his attacker.

"You must be getting slower in your old age," he taunted, narrowly avoiding the carving knife which whizzed past his ear.

"Herbivore," Hibari snarled. "Stop running away and fight me properly!"

"One who fights and runs away, lives to fight another day," Mukuro half-sang, skipping back another few steps only to trip over a bottle and crash to the floor. In an instant, a tonfa was pressed to his throat.

"Only if that coward is more intelligent than you are," Hibari said, smirking.

Mukuro sighed and threw his hands up in defeat as Tsuna came rushing in.

"I told you two: no fighting here! Please!" Tsuna exclaimed, his voice attaining that higher pitch only heard in moments of panic.

Without a word, Hibari removed his weapon from Mukuro's neck and the latter sat up, wincing. Now that it was safe, the others came over to help clean up the mess. Tsuna stared, surprised that Hibari had stopped fighting so quickly but glad nonetheless.

"A-are you alright, Mukuro?" he asked hesitantly as the man climbed to his feet.

"I could be worse. Considering this is Kyoya we speak of." He returned the Cloud Guardian's simmering glare with a light, humorous smile.

That was true - their most intense fights often ended with one or the other (occasionally both) confined to the infirmary for an extended period of time.

"Um..." Would it be pointless to try and dissuade them from their constant clashes? Tsuna sighed. "When will the two of your resolve your grudge...? It's been going on for ten years now..."

"We _have_ resolved it."

Tsuna blinked. "Eh?"

"I said we have resolved it already," Mukuro repeated.

Tsuna blinked some more times and looked between the two Guardians. "But...you two are always..."

"We were bored."

_Bored...?_ Tsuna's thoughts exclaimed incredulously. His spoken words were not much less alarmed. "Is that it? Boredom?"

"Fighting each other is a past-time for us. A game, if you will, Tsunayoshi," Mukuro explained.

Tsuna could not believe what he was hearing. Wounding one another to the point of death was a _game_ to them? "H-hurting each other like that...almost killing each other! Doesn't it...well, hurt?"

Both Guardians were mute on that point. Mukuro stared straight ahead while Hibari frowned at the floor.

"It is nothing unusual..." Mukuro finally said quietly.

"...nothing compares...bastard...humiliated me..." Tsuna heard Hibari mutter disjointedly.

_These two_... Tsuna thought, looking from one to the other, _these two have both suffered so much pain. Hibari at Mukuro's hands, and Mukuro who won't say anything about his past, but no doubt had someone or some people who were cruel to him. I don't believe anyone is born with so much hate. All either of them knows is how to retaliate, to fight back against all odds. The only way they can improve is by fighting each other. They are supposed to be enemies after all - who would question them?_

Even so, there was something that had grown within them during their time spent with each other. What he had seen - not just that moment a few hours ago - what he had observed over the past months was a closeness that defied the limits of friendship. Their animosity for each other could only be a facade worn by two people who were used to concealing their true emotions. So much so that they even deceived their own selves.

Tsuna made his voice and stance firm. "Alright." Everyone looked to him, perceiving his sudden change in attitude. "Mukuro, Hibari: I want you two to kiss each other."

Gokudera - predictably - had the loudest reaction. His ear-ringing "WHAT?" was enough to completely override Yamamoto's bemused laughter and much quieter echo of the same sentiment ("Haha, what?") as well as Ryohei's enthusiastic yell ("_Extreme!_") which was accompanied by a fist punching the air. Lambo merely blinked his droopy cow-eyes while the girls clapped hands to their mouths and gasped.

Mukuro and Hibari were staring at him, no less shocked, but trying not to let it to show.

"You cannot be serious, Tsunayoshi..."

"I would never kiss anyone, let alone that herbivore—!"

"That is an order," Tsuna affirmed. "I am the Vongola Decimo, and if you recognise me as such, you will kiss each other." He hated pulling rank on anyone but nothing else would suffice when dealing with Hibari or Mukuro. His eyes threatened to deepen into a burnished, fiery copper while his voice became slower, calmer, more authoritative.

Tsuna could see the two weighing up his words, analysing the situation and considering their next move. Tsuna sincerely hoped that the thought of teaming up against him did not enter their minds. He could be a match for either one, maybe, in Dying Will mode, but both at the same time?

Mukuro chuckled. "Kyoya, it seems we have no choice but to obey a direct order from the Decimo. May I have your leave to kiss you?" Smiling faintly, he made an extravagant bow in the Cloud Guardian's direction and held it, raising his head to watch the other man's reaction as he awaited a reply.

Hibari made a noise of disgust. He folded his arms, scowling at Mukuro. "There is no way I—" He stopped abruptly when Mukuro suddenly appeared right in front of him and kissed him anyway, cupping his chin in one hand and pressing their lips together.

Hibari's eyes flashed at the intimate contact. Usually Tsuna would have expected him to shove the other man away violently. Indeed, that thought did seem to occur to Hibari who had instinctively raised his hands with that very intention. But as several tense seconds ticked by, Tsuna saw uncertainty in his Cloud Guardian's eyes. Hibari's hands hovered where they were as the man deliberated on how he would react...

Everyone had fallen silent.

Then Hibari visibly relaxed, closing his eyes, embracing Mukuro and deepening their kiss.

Wolf-whistles and cheers sounded in the kitchen. The two separated, turning to their appreciative spectators with faintly-tinged faces as they were swamped with a round of hugs and back-slapping – until Hibari sent all of them scattering back to a respectable distance where instead they formed an untidy ring.

Tsuna smiled, seeing the faint happiness that shone through the new crack in his two Guardians' emotional armour - Mukuro's smile less mocking, Hibari glaring not with anger but embarrassment. Gokudera came over to stand beside him, the only one apart from Tsuna who had not rushed over.

"Hibari and Mukuro, eh?" The Storm Guardian ran his fingers through his silver hair and vented a drawn-out sigh. "I wonder when they crossed that line between love and hate."

Tsuna flipped back through his memories, trying to recall all those moments he had dismissed previously as accidents: 'casual' touches, teasing bordering on flirting...and shook his head, smiling a little wider.

"I think they crossed the line long ago." He looked over at Hibari and Mukuro, now holding hands. "They just didn't realise it."


End file.
